Mail box signal



FIG. 1 is a perspective view of a mail box signal showing my new design, it being understood that the broken lines are for illustrative purposes only;

FIG. 2 is a perspective view thereof in an alternate position;

FIG. 3 is a front elevational view thereof; and

FIG. 4 is a side elevational view thereof. 

The ornamental design for a mail box signal, as shown and described. 